Carburetor



B. BEARD CARBURETOR June 19, 1934.

Original Filed Jan. 22, 1950 INVENTOR ATTORNEY \l I l l I l l l I :l

13.674?? E edf@ 'Patented June I9, 1934 PATENT OFFICE UNITED STATES CARBURETOR Bert Beard, Detroit, Mich., assignor to George M. Holley, Detroit, Mich.

Application January. 22, 1930, Serial No. 422,516

Renewed July s, 1932 s claims. (01.*261-49) ow of air through the mixing chamber to ensure y a steady and adequate supply of fuel to run the engine, further on opening the throttle the transfer from idle to widefopen is not Imade without an interruption to the fuel flow, for a similar reason. If the mixing chamber is restricted the engine does not get a full charge of air at wide open throttle at maximum engine speed. Specific means are provided in this invention to correct go this defect.

Figure 1 shows in elevation the novel parts and shows in partial elevation the parts which are common to all carburetors of this type. These latter portions are no t shown in complete detail.

Figure 2 shows a small detail.

In the figures A is the air entrance, B is the mixture outlet, C is the throttle valve therein, D is the float chamber containing the usual oat mechanism (which is not shown), the mechanism maintains the fuel at the level X-X. F is the mixing chamber, G is the fuel nozzle discharging therein. H- is the low speed fuel orifice located in the low speed fuel plug K, controlled by the lever J. This low speed fuel orice is fed through the passages LM (shown in broken lines). The fuel nozzle G is fed through a passage N (shown in broken lines). This passage N also furnishes the fuelfor vthe low speed passage M. A yent plug 0 is provided located above-the level X-X 4- to prevent the nozzle G and the low speed nozzle H siphoning the fuel out of thefloat chamber D. For obvious reasons this vent O must be at least ik" above the level X-X. P is a lever mounted on a throttle shaft Q. Two Alinks are connected to P one of them lettered R controlling a valve S which provides additional air around the mixing jchamber F. The lvalve S is controlled by a lever T and a spring U is interposed between the link R and the lever T for a purpose to ,be described 5g later.` The other end of the lever P'is connected through a link V and an arm W with a valve Y which admits fuel through the passage Z into the mixing chamber F at a point E below the level X'X of the oat chamber D. The opening E is restricted so that the flow through E under the headv X-X gives the desired additional fuel. It must be understood of course that the fuel nozzle G is more complex than shown, and in addition a fuel pump `of the type shown in my copending application 338,934 will also be required to satisfy the owners of modern high speed automobile engines IIt will be noted that the` passage Z communicates at its upper end with the air entrance A. J Operation When the engine is running slowly the throttle C being in a closed position, the fuel is drawn up N and down M through orice H into the mixing chamber B. With the throttle S in the closed position and the spring U is compressed, it will y be noted that the arm of the 1ever T, which is connected tothe link R, is shorter than the arm of the lever P which is connected to R. As the throttle P is opened the spring U expands and '15k the valve S remains closed, all the air entering at A is thus forced to'pass through F and the depression created therein causes the fuel to ow vup N and down M into the mixing chamber F. When the throttle is approximately 3A 80 open .the spring U' causes the valve S to open, when the throttle C is Wide opefn the throttle S is also wide open. Simultaneous with the opening of S the valves Yrropen admitting fuel directly from the ,oat chamber D into-the mixing chamber F through the lrestricted orifice E which is located below the level X-V-X. This fuel ows down Z being entrained by the air flowing through Z and discharges into the venturi F.

What I claim is:

1.'A downdraft carburetorhaving a mixing chamber, a mixture outlet, a throttle valve therein, a constant level fuelsupply chamber, a suction controlled fuel nozzle supplied therefrom supplying fuel'to Asaidmixing chamber, a gravity 95 fed fuelnozzle supplying fuel from said supply chamber to said mixingchamberat a point below said constant level, means 'for holding said gravity fed vfue1 nome open on1y when the throttle .is substantially in the wide open position.

2.'A downdraft carburetor havingt a mixing chamber, a mixture outlet, a throttle valve therein, a constant level fuel supply chamber, a suctionfcontrolled fuel nozzlesupplied therefrom supplying fuel to said mixing chamber, a gravity fed fuel nozzle supplying fuel from said supply l chamber to said mixing chamber to a point below said constant level, means for holding said gravity fed fuel nozzle'open onlywhen the throttle is substantially in the wide openposition, means for esl admitting an extra quantity of air into said mixsupply chamber to said mixing chamber at a point ture outlet when the gravity fed fuel nozzle is below said constant level, means for closing said brought into operation. gravity fuel nozzle when the throttle is moved to 3. A downdraft carburetor having a mixing the closed position whereby the gravity fed nozzle 5 chamber, a mixture outlet, a throttle valve thereceases to deliver' fuel, when the throttle is moved 80 in, a constant level fuel supply chamber, a suction a substantial degree away from Vthe wide open controlled fuel nozzle supplied therefrom supplyposition. ing fuel to said mixing chamber at all times, a`

o gravity fed fuel nozzle supplying fuel from said l BERT BEARD. 85 

